/Engine/Source/Editor/UnrealEd/Public/Layers/LayersSubsystem.h
Add the actors to the named layer
true if at least one actor was added to the layer. false is returned if all the actors already belonged to the layer.
virtual bool AddActorsToLayer ( const [TArray](API\Runtime\Core\Containers\TArray)< [TWeakObjectPtr](API\Runtime\Core\UObject\TWeakObjectPtr)< [AActor](API\Runtime\Engine\GameFramework\AActor) > > & Actors, const [FName](API\Runtime\Core\UObject\FName) & LayerName )